On a weekend, Shin taro, a diligent office worker living somewhere in Tokyo who deeply values his family, is busy cleaning the house in preparation for the arrival of his wife's mother, his stepmother-in-law, who is coming to visit from her hometown. Since his wife lives in the countryside, her mother has traveled all the way to Tokyo. The doorbell rings, and in walks Yuri Uesato—his voluptuous, mature stepmother-in-law—whose striking, sensual figure instantly takes Shin taro's breath away, making his heart race as he welcomes her. A story unfolds where familial warmth intertwines with the quiet birth of a forbidden, intimate connection.